1. Field of the Invention
The present invention relates to a copy preventing system for preventing unauthorized copying or utilization of copyrighted multi-media digital information when such information is provided to a multi-media equipment owned by a user in form of communication or broadcasting media or package media.
2. Description of the Related Art
With development and progress of digital information technique in recent years, various types of multi-media information such as audio information or visual information are digitalized and offered to users. Because the information is not deteriorated even when it is repeatedly copied, the infringement of copyright by copying is a serious problem. In particular, digital ROM information such as the information on a compact disk (CD) is widely propagated and large capacity media are now used in practical application, by which the user can record digital information. This creates a situation where unauthorized copying of the information can be carried out in a relatively easy manner.
However, the conventional type multi-media equipment as described above is not provided with the function to restrict copying of the information or to limit copying beyond a certain extent. For this reason, when copyright information is offered, importance is now put on information protective system to prevent unauthorized copying and to maintain security of the offered information. At present, a relatively simple copy preventing system such as SCMS (serial copy management system) is used in practical application, which permits second-generation copying, i.e. re-copying, but not the third generation copying, i.e. re-re-copying, in digital audio tape (DAT) and the like. This is merely to restrict copying of information recorded on a recording medium DAT, and does not provide a security guard on the information itself, which is the content of the recording. It is currently expected that there will be more demand on the system, which can cope with the diversified requirements of the copyright information providers or the users. More advanced digital information providing means is expected to appear in near future, and large capacity digital information recording medium writable by the users will be used in practical application.
In particular, to the propagation of high-speed information network aiming at home or private users or of large capacity digital medium such as digital video disk (DVD), systematic measures should be taken for the prevention of illegal or unauthorized copying.